A Rapid Hierarchical Rendering Technique for Translucent Materials

Henrik Wann Jensen
Stanford University

and

Juan Buhler
PDI/DreamWorks

Hierarchical BSSRDF Evaluation

Our new hierarchical evaluation technique is fast and it integrates
seamlessly with traditional global illumination techniques such as
photon mapping used in this Cornell box image. Note the light bleeding
through the translucent box.

Abstract

This paper introduces an efficient two-pass rendering technique for
translucent materials. We decouple the computation of irradiance
at the surface from the evaluation of scattering inside the material.
This is done by splitting the evaluation into two passes, where the
first pass consists of computing the irradiance at selected points
on the surface. The second pass uses a rapid hierarchical integration
technique to evaluate a diffusion approximation based on the irradiance
samples. This approach is substantially faster than previous methods for
rendering translucent materials, and it has the advantage that
it integrates seamlessly with both scanline rendering and global
illumination methods. We show several images
and animations from our implementation that demonstrate that the
approach is both fast and robust, making it suitable for rendering
translucent materials in production.